WESTPORT, CT (Reuters Health) - Aerobic exercise can increase women's bone
density, and it need not be a high-impact exercise regimen, new research
shows.

In fact, recommendations for general health--walking for about 30 minutes a
day, a few days a week--is enough improve bone mass, Dr. George A. Kelley, of
the MGH Institute of Health Professions in Boston, an affiliate of
Massachusetts General Hospital, told Reuters Health.

In a review of 24 studies that examined aerobic exercise and bone mineral
density in women, Dr. Kelley's team found that, on average, regular
exercisers saw about a 2% bone mass gain over non-exercisers.

Whether the modest gain translates into a lower risk of osteoporosis and
related fracture is unclear, Dr. Kelley said. However, he added, because
exercise improves balance and coordination, it could also reduce older
women's odds of falling.

Dr. Kelley presented the study findings last week in Atlanta, Georgia, at the
annual meeting of the American Public Health Association.

Dr. Kelley's team analyzed studies that included women who were 18 years and
older, the majority of whom were sedentary. In each study, some women were
assigned to an aerobic exercise regimen that lasted at least 16 weeks.

Walking was the most common form of exercise used in the studies, Dr. Kelley
said. On average, women walked about a half hour, 3 days a week.

Overall, women who exercised gained close to 0.4% in bone mineral density in
the lumbar vertebrae, while non-exercisers saw a decrease of nearly 2%.
Exercisers also had femoral increases of 1.4%, while non-exercisers recorded
a loss of about 0.6%.

The benefits were similar among premenopausal and postmenopausal women, Dr.
Kelley noted.

The good news from this study is that the most popular form of exercise in the
US--walking--can give a lift to bone mass, according to Dr. Kelley.

Since strength training with weights also helps bone density, he added, the
ideal exercise plan includes aerobics and weights.